## My Tip to Solving Remainder Problems

Questions about the world of GMAT Math from other sources and general math related questions.
DennaMueller
Course Students

Posts: 15
Joined: Fri Dec 12, 2008 5:12 am

### My Tip to Solving Remainder Problems

I am having trouble with these problems, so I came up with a way to memorize the formula. The instructors can post if there is anything wrong with my logic.

This is the formula from Manhattan GMAT Number Properties Guide:
x=QN+R
x = Dividend
Q = Quotient
N = Divisor
R = Remainder

I changed the symbols in the formula to this:
T=QB+R
This I can remember with the phrase 'a touchdown equals the quarterback plus the receiver'.
T = Top of the fraction
Q = Quotient
B = Bottom of the fraction
R = Remainder

The Question:

If T divided by B equals 8.12 what is a possible remainder?
2
8
9
26
44

T=800B+.12
Now make .12 an integer
100T=800B+12
Simplify by dividing by 4
25T=200B+3
Now the Remainder is (3), so any remainder of T/B must be a multiple of 3
This makes my answer to the problem C - 9
tomslawsky
Students

Posts: 138
Joined: Wed Jul 15, 2009 12:07 pm

### Re: My Tip to Solving Remainder Problems

I remember this by just remembering that the remainder must be a whole multiple of the decimal:

18/.12= whole number
Ben Ku
ManhattanGMAT Staff

Posts: 817
Joined: Sat Nov 03, 2007 7:49 pm

### Re: My Tip to Solving Remainder Problems

This formula can be a helpful way to approach remainder problems. I would recommend it when you know the reason why the formula works. This way you know when to use it and when not to.

Thanks!
Ben Ku
Instructor
ManhattanGMAT
garimaash
Students

Posts: 2
Joined: Sun Sep 20, 2009 5:15 pm

### Re: My Tip to Solving Remainder Problems

Sorry.. Pls refer to the post below..
Last edited by garimaash on Fri Nov 13, 2009 7:23 am, edited 1 time in total.
garimaash
Students

Posts: 2
Joined: Sun Sep 20, 2009 5:15 pm

### Re: My Tip to Solving Remainder Problems

tomslawsky wrote:I remember this by just remembering that the remainder must be a whole multiple of the decimal:

18/.12= whole number

I didn't understand this.. Could you pls elaborate?
ryan.vineyard
Course Students

Posts: 2
Joined: Sun Jun 28, 2009 4:00 pm

### Re: My Tip to Solving Remainder Problems

Ben Ku
ManhattanGMAT Staff

Posts: 817
Joined: Sat Nov 03, 2007 7:49 pm

### Re: My Tip to Solving Remainder Problems

DennaMueller wrote:I changed the symbols in the formula to this:
T=QB+R
This I can remember with the phrase 'a touchdown equals the quarterback plus the receiver'.
T = Top of the fraction
Q = Quotient
B = Bottom of the fraction
R = Remainder

A numerical example is this:
13 Ã· 4 = 3 R 1
However, you should remember that it really is just 13 Ã· 4 = 3 + 1/4 or 3.25. So you see that the ".25" part of the answer is just "R / B". If we can write the decimal part as a fraction, then we can determine what might be the remainder.

DennaMueller wrote:The Question:

If T divided by B equals 8.12 what is a possible remainder?
2
8
9
26
44

We just need to figure out how express ".12" into a fraction. Well, the easy fraction here is "12/100." This can be simplified to "3 / 25" which is "R / B". So we know that the remainder must be a multiple of 3 for this to be true.

Hope that makes sense.
Ben Ku
Instructor
ManhattanGMAT